Apparatus and methods for connecting fuel cells to an external circuit

ABSTRACT

Various embodiments of the present invention provide a fuel cell connection component, including an interconnect or a current collector. The fuel cell connection component includes conductive fibers oriented at an angle of less than about 90° to at least one electrode in the fuel cell. The fuel cell connection component provides an electrically conductive pathway from the at least one electrode of the fuel cell to an external circuit or to an electrode of a different fuel cell. Embodiments of the present invention also provide fuel cells that include the fuel cell connection component, including fuel cell layers, and methods of making the same.

CLAIM OF PRIORITY

This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 12/980,130, filed Dec. 28, 2010, which claims thebenefit of priority under 35 U.S.C. Section 119(e), to U.S. ProvisionalPatent Application Ser. No. 61/290,450, filed Dec. 28, 2009; which arehereby incorporated by reference herein in its entirety.

BACKGROUND

Fuel cells may be employed as a power supply for an increasing number oflarge-scale applications, such as materials handling (e.g. forklifts),transportation (e.g. electric and hybrid vehicles) and off-grid powersupply (e.g. for emergency power supply or telecommunications). Smallerfuel cells are now being developed for portable consumer applications,such as notebook computers, cellular telephones, personal digitalassistants (PDAs), and the like.

In a typical prior art fuel cell stack, electrons travel from themembrane electrode assembly (MEA) of a unit fuel cell through aseparator plate to the MEA of the next unit cell. Typically, at each endof a fuel cell stack, current is supplied to or from an external circuitvia connection components, including bus plates and connectors.Conventional fuel cell stacks may require numerous seals and theapplication of compressive force to prevent leakage of fuel and oxidantand to ensure good electrical contact between separator plates, MEAs andbus plates. Fuel cell stacks can therefore require many parts andassembly can be quite complex.

Fuel cells may also be connected in edge-collected configurations, suchas planar configurations. In such fuel cell systems, current iscollected from the edges of individual unit cells and travels in theplane of the fuel cells. In such fuel cell systems, the spatialarrangement of components may be different from the spatial arrangementof components in a conventional fuel cell stack. In such fuel cellsystems, the predominant direction of electron flow may be differentfrom the predominant direction of electron flow in a conventional fuelcell stack. In some of such fuel cell systems, the desired properties ofcomponents may be different from the desired properties of components ina conventional fuel cell stack.

Some edge-collected or planar fuel cell systems do not employcompressive force in order to maintain good contact between the fuelcell layer and various other components of the fuel cell system. In suchfuel cell systems, components may be assembled and held in contact byother means. Accordingly, components that are employed in a conventionalfuel cell stack for connection to an external circuit may not be optimalfor employment in edge-collected fuel cell systems.

In a single fuel cell, minor electrical resistance from components canbe relatively inconsequential. However, when multiple fuel cells areused, such as in a stack or planar fuel cell system, electricalresistance from components can accumulate to create a comparativelylarge internal resistance within the array. A large internal resistancecan decrease performance of a fuel cell system with multiple cells,including a stack or planar fuel cell system.

SUMMARY

Various embodiments of the present invention provide a fuel cellconnection component, including an interconnect or a current collector.The fuel cell connection component includes conductive fibers orientedat an angle of less than about 90° to at least one electrode in the fuelcell. The fuel cell connection component provides an electricallyconductive pathway from the at least one electrode of the fuel cell toan external circuit or to an electrode of a different fuel cell.Embodiments of the present invention also provide fuel cells thatinclude the fuel cell connection component, including fuel cell layers,and methods of making the same.

Various embodiments of the present invention provide certain advantagesover other fuel cell connection components, fuel cells, or fuel celllayers, some of which are surprising and unexpected. One of skill in theart would generally assume that the highest conductivity in a fuel cellconnection component using conductive fibers could be achieved byforming the shortest and most direct conductive path in that component.In a fuel cell conducting component, this can involve arranging a firstset of conductive fibers such that they form a right angle with theelectrode. However, for example, surprisingly and unexpectedly, in someembodiments it has been found that by orienting the conductive fiberssuch that they form an angle of less than 90° with the electrode orelectrode coating, such as for example 45°, conductivity of the fuelcell connection component can be higher than that of a fuel cellconnection component with the conductive fibers oriented at about 90° tothe electrode or electrode coating. Further, for one of skill in the artto arrange conductive fibers in a fuel cell connecting component toachieve the shortest path, this can involve arranging a second set ofconductive fibers such that they form an approximate right angle withthe first set of conductive fibers (e.g. the first and second set ofconductive fibers form a grid), such that the second set of conductivefibers are parallel to the length of the fuel cell conducting component.This is especially the case for interconnects, wherein current cantravel along the length of the interconnect to an external circuit.However, in another example, surprisingly and unexpectedly, by includinga first set of conductive fibers and a second set of conductive fibersin the fuel cell connection component, both of which form an angle ofless than about 90° with the electrode or electrode coating, such as forexample 45°, and each of which forms an approximately 90° angle witheach other (e.g. the first and second set of conductive fibers form agrid), conductivity of the fuel cell connection component is higher thanthat of a fuel cell conducting component that includes a first andsecond set of conductive fibers, one of which forms an approximately 90°angle with the electrode or electrode coating, and each of which formsan approximately 90° angle with one another. In another example, theconductive fibers of some embodiments of the present invention are morefirmly bonded and more difficult to pull out of the fuel cell connectioncomponent than in other fuel cell connection components, including fuelcell connection components that have conductive fibers oriented at anapproximately 90° angle with the electrode or electrode coating, andincluding fuel cell connection components that have a first set ofconductive fibers oriented at an approximately 90° angle with theelectrode or electrode coating and a second set of conductive fibersoriented at an approximately 90° angle with respect to the first set ofconductive fibers. In another example, some embodiments of the presentinvention can have greater strength or durability than other fuel cellconnection components. In another example, some embodiments of thepresent invention can be made using less compressive force than otherfuel cell connection components. In another example, some embodiments ofthe present invention that do not include conductive fibers orientedapproximately along the length of the fuel cell connection component canbe more flexible or less rigid than other fuel cell connectioncomponents, including more flexible than fuel cell components thatinclude conductive fibers oriented approximately parallel to the lengthof the component. In a another example, surprisingly and unexpectedly,some embodiments of the fuel cell connection component can have theadvantages discussed herein, including higher conductivity, more securebinding of conductive fibers, greater strength, greater durability, orless compressive force needed during manufacture, without an increase incomplexity, price, changes in materials, or other substantial changes inmanufacturing processes.

The present invention provides a fuel cell connection component. Thefuel cell connection component includes a non-conductive interfaceregion. The non-conductive interface region has a first surface and asecond surface. The fuel cell connection component also includes anelectron conducting component. The electron conducting component has twosurfaces and a length that is parallel to the two surfaces of theelectron conducting component. One of the surfaces of the electronconducting component is disposed adjacent to the second surface of theinterface region. The electron conducting component includes conductivefibers. The conductive fibers are oriented approximately parallel to thetwo surfaces of the electron conducting component. The conductive fibersare adapted to be oriented at an angle of less than about 90° to atleast one electrode in a fuel cell. The fuel cell connection componentalso includes a binder. The binder holds the interface region and theelectron conducting component together. The fuel cell connectioncomponent is adapted for use in the fuel cell such that it provides anelectrically conductive path between the at least one electrode or thefuel cell and an external circuit or between the at least one electrodeof the fuel cell and at least one electrode of a different fuel cell.

The present invention provides a fuel cell. The fuel cell includes anion conducting component. The fuel cell also includes two or moreelectrode coatings. The fuel cell also includes one or more fuel cellconnection components. The fuel cell connection components include anon-conductive interface region. The non-conductive interface region hasa first surface and a second surface. The first surface of thenon-conductive interface region is in contact with the ion conductingcomponent. The fuel cell connection components also include an electronconducting component. The electron conducting component has two surfacesand a length that is parallel to the two surfaces of the electronconducting component. One of the surfaces of the electron conductingcomponent is disposed adjacent to the second surface of the interfaceregion. The electron conducting component includes conductive fibers.The conductive fibers are oriented approximately parallel to the twosurfaces of the electron conducting component. The conductive fibers areoriented at an angle of less than about 90° to one of the electrodecoatings. The electron conducting component provides an electricallyconductive pathway between the one electrode coating and an externalcircuit or between the one electrode coating and an electrode coating ofanother fuel cell. The pathway extends along the length of the electronconducting component.

The present invention provides a fuel cell layer. The fuel cell layerincludes a composite layer. The composite layer includes a first surfaceand a second surface. The composite layer includes a plurality of fuelcell connection components. The composite layer includes a plurality ofion conducting components. The ion conducting components are positionedbetween the fuel cell connection components. The composite layer alsoincludes a first plurality of electrode coatings. The first plurality ofelectrode coatings are disposed on the first surface to form anodes. Thecomposite layer also includes a second plurality of electrode coatings.The second plurality of electrode coatings is disposed on the secondsurface to form cathodes. Each of the first and second plurality ofelectrode coating is in ionic contact with one of the ion conductingcomponents and in electrical contact with one of the fuel cellconnection components. At least one of the fuel cell connectioncomponents includes an interface region. The interface region has afirst surface and a second surface. The first surface is in contact withone of the ion conducting components. The at least one fuel cellconnection component also includes at least one electron conductingcomponent. The at least one electron conducting component has twosurfaces and a length parallel to the two surfaces. One of the surfacesof the at least one electron conducting component is disposed adjacentto the second surface of the interface region. The at least one electronconducting component includes conductive fibers. The conductive fibersare oriented approximately parallel to the two surfaces of the at leastone electron conducting component. The conductive fibers are oriented atan angle of less than about 90° to at least one of the first or secondplurality of electrode coatings. At least one of the fuel cellconnection components provides an electrically conductive pathwaysbetween the at least one of the first or second plurality of electrodecoatings and an external circuit or between one of the first or secondplurality of electrode coatings and a different one of the first orsecond plurality of electrode coatings. The pathway extends along thelength of the at least one electron conducting component.

Embodiments of the present invention relate to a fuel cell including, anion conducting component, two or more electrode coatings and one or moreinterconnects. The interconnects include a non-conductive interfaceregion having a first surface and a second surface in which the firstsurface is in contact with the ion conducting component, an electronconducting component having two surfaces and a length that is parallelto the two surfaces wherein one of the surfaces is disposed adjacent tothe second surface of the interface region. The electron conductingcomponent provides an electrically conductive pathway between one of theelectrode coatings and an external circuit, said pathway extending alongthe length of the electron conducting component.

Embodiments of the present invention also relate to a fuel cell layerincluding a composite layer having a first surface and a second surface,the composite layer including a plurality of current collectors and aplurality of ion conducting components positioned between the currentcollectors, a plurality of anode coatings disposed on the first surfaceand a plurality of cathode coatings disposed on the second surface, eachcoating in ionic contact with one of the ion conducting components andin electrical contact with one of the current collectors. At least oneof the current collectors includes an interface region having a firstsurface and a second surface, the first surface in contact with one ofthe ion conducting components; and, an electron conducting componenthaving two surfaces and a length parallel to the two surfaces, one ofthe surfaces disposed adjacent to the second surface of the interfaceregion; and wherein the at least one of the current collectors providesan electrically conductive pathway between one of the electrode coatingsand an external circuit, said pathway extending along the length of theelectron conducting component.

Embodiments of the present invention also relate to a method of makingan interconnect for a planar fuel cell including contacting a firstelectrically conductive material and a second electrically conductivematerial, sufficient to form a layered structure, curing the layeredstructure sufficient to provide a preform, optionally coating thepreform sufficient to provide a coated preform, optionally disposing afiller on the preform, optionally activating the preform, curing thepreform sufficient to provide an interconnect sheet and optionallycutting the interconnect sheet, sufficient to form interconnects.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe substantially similar components throughout the several views.Like numerals having different letter suffixes represent differentinstances of substantially similar components. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present document.

FIGS. 1A-B are cross-sectional schematic diagrams of a conventionalprior art fuel cell stack.

FIGS. 2A and 2B are cross-sectional views of, respectively, a firstexample planar fuel cell layer and a second example planar fuel celllayer.

FIGS. 3A-D are perspective schematic and graphical diagrams of unit fuelcell 120 in the example planar fuel cell layer 100.

FIGS. 4A-4H are truncated sectional views of an interconnect within aunit cell, according to several example embodiments.

FIG. 5 is a sectional view of a fuel cell system employing theinterconnect of FIG. 4G, according to an example embodiment.

FIGS. 6A and 6B are top perspective views of partial fuel cell systemsemploying interconnects, according to example embodiments.

FIG. 7 is a block process diagram of one possible method of preparinginterconnects, such as the interconnects illustrated in of FIG. 4E-4G.

FIG. 8A is a top view of fuel cell connection component, in accordancewith various embodiments.

FIG. 8B is a side view of a fuel cell connection component, inaccordance with various embodiments.

FIG. 9A is top view of a fuel cell connection component, in accordancewith various embodiments.

FIG. 9B is a side view of a fuel cell connection component, inaccordance with various embodiments.

DETAILED DESCRIPTION

Throughout the following description, specific details are set forth inorder to provide a more thorough understanding of the invention.However, the invention may be practiced without these particulars. Inother instances, well known elements have not been shown or described indetail in order to avoid unnecessarily obscuring the invention. Thedrawings show, by way of illustration, specific embodiments in which theinvention may be practiced. These embodiments may be combined, otherelements may be utilized or structural or logical changes may be madewithout departing from the scope of the invention. Accordingly, thespecification and drawings are to be regarded in an illustrative, ratherthan a restrictive, sense.

All publications, patents and patent documents referred to in thisdocument are incorporated by reference herein in their entirety, asthough individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated referencesshould be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used to include one or morethan one, independent of any other instances or usages of “at least one”or “one or more”. In this document, the term “or” is used to refer to anonexclusive or, such that “A, B or C” includes “A only”, “B only”, “Conly”, “A and B”, “B and C”, “A and C”, and “A, B and C”, unlessotherwise indicated. The terms “above” and “below” are used to describetwo different directions in relation to the center of a composite andthe terms “upper” and “lower” may be used to describe two differentsurfaces of a composite. However, these terms are used merely for easeof description and are not to be understood as fixing the orientation ofa fuel cell layer of the described embodiments. In the appended aspectsor claims, the terms “first”, “second” and “third”, etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

Embodiments of the present invention describe fuel cell interconnectcomponents and fuel cell architectures that provide a means ofconnecting a circuit to the ends of a fuel cell layer. Embodiments alsoprovide a more conductive path along the current collector path lengthwhere current is higher. Additionally, embodiments provide a conductivebut corrosion resistant interface to the electrochemical components in afuel cell system. Current collector and interconnect designs of thepresent embodiments may include two different types of materials, withdifferent conductivities and contamination properties used incombination to provide high conductivity where needed while alsopreventing the introduction of corrosion properties into the fuel celllayer.

Provided are interconnects, for connecting an edge-collected fuel celllayer to an external circuit. Interconnects include electron conductingcomponents and optionally, interface regions. Electron conductingcomponents include one or more electrically conductive materials.Electron conducting components may include two or more electronconducting regions, having different composition. Interface regionsinclude one or more non-conductive materials.

Provided are fuel cells, fuel cell layers and fuel cell systemsincluding interconnects. Interconnects may be employed in a fuel cell,fuel cell layer or fuel cell system to provide high electricalconductivity in a direction that is parallel to the length of the fuelcell while isolating active components of the fuel cell fromcontamination with corrosion products. Interconnects of some embodimentsmay be included in fuel cell systems that do not employ compressiveforce to maintain contact between components of the fuel cell system. Insome embodiments, interconnects may be simpler to connect to an externalcircuit.

Embodiments of the invention have been described as proton exchangemembrane (PEM) fuel cells or components of PEM fuel cells. However,embodiments of the invention may be practiced with other types of fuelcells, such as alkaline fuel cells or solid oxide fuel cells.Embodiments of the invention may also have application in other types ofelectrochemical cells, such as electrolyzers or chlor-alkali cells.

Fuel cell assemblies according to some embodiments may be used as asource of power for various applications. For example, fuel cell systemsmay be used to power portable consumer devices, such as notebookcomputers, cellular telephones or PDAs. However, the invention is notrestricted to portable consumer devices and embodiments may be practicedto power larger applications, such as materials handling applications,transportation applications or off-grid power generation; or othersmaller applications.

Embodiments of the invention may be practiced with fuel cells of avariety of different designs. Described herein is the practice ofembodiments with planar fuel cells. However, the same or otherembodiments may alternatively be practiced with other types ofedge-collected fuel cells. For ease of reference, throughout thedescription, fuel cells and related technology are referred to as“planar” fuel cells, “planar” fuel cell assemblies or “planar” fuel celllayers. However, it is to be understood that fuel cells may not beplanar and edge-collected fuel cells need not be planar to be practicedwith the invention. For example, unit fuel cells may not all lie in thesame plane (e.g. they may be flexible, spiral, tubular, or undulating).

DEFINITIONS

As used herein, “catalyst” refers to a material or substance thatassists in starting or increasing the rate of a reaction, without beingmodified or consumed itself. Catalyst layers may comprise any type ofelectrocatalyst suitable for the application at hand. Catalysts orcatalyst layers may include pure platinum, carbon-supported platinum,platinum black, platinum-ruthenium, palladium, copper, tin oxide,nickel, gold, mixtures of carbon black and one or more binders. Bindersmay include ionomers, polypropylene, polyethylene, polycarbonate,polyimides, polyamides, fluoropolymers and other polymer materials, andmay be films, powders, or dispersions. An example of a polyimideincludes Kapton®. An example of a fluoropolymer is PTFE(polytetrafluoroethylene) or Teflon®. Other fluoropolymers include PFSA(perfluorosulfonic acid), FEP (fluorinated ethylene propylene), PEEK(poly ethylene ether ketones) and PFA (perfluoroalkoxyethylene). Thebinder may also include PVDF (polyvinylidene difluoride) powder (e.g.,Kynar®) and silicon dioxide powder. The binder may include anycombination of polymers or ionomers. The carbon black may include anysuitable finely divided carbon material such as one or more of acetyleneblack carbon, carbon particles, carbon flakes, carbon fibers, carbonneedles, carbon nanotubes, and carbon nanoparticles.

As used herein, “coating” refers to a conductive thin-layer disposed onthe surface of a composite layer. For example, the coating may be acatalyst layer or electrodes, such as anodes and cathodes.

As used herein, a “composite layer” or “composite” refers to a layerincluding at least two surfaces having a thickness, where one or moreion conducting passages and one or more electrically conductive passagesare defined between the surfaces. Ion conducting properties andelectrically conductive properties of a composite can be varied indifferent regions of the composite by defining ion conducting passagesand electrically conductive passages with varying sizes, shapes,densities or arrangements. A composite layer may also include one ormore interface regions. A composite layer may be impermeable, orsubstantially impermeable, to a fluid (e.g. a gas or a liquid).

As described herein, an “electron conducting component” refers to acomponent of a composite layer that provides an electrically conductivepathway. The electron conducting component may provide an electricallyconductive pathway, or pathways, from one surface of a composite layer,through the composite, to the opposite surface of the composite layer,for example. Electron conducting components include one or morematerials that are electrically conductive, for example, metals, metalfoams, carbonaceous materials, electrically conductive ceramics,electrically conductive polymers, combinations thereof, and the like.Electron conducting components may also include materials that are notelectrically conductive. Electron conducting components may also bereferred to herein as “current conducting components,” “currentcollectors,” “interconnects,” or “fuel cell connection components.”

As used herein, an “ion conducting component” refers to a component thatprovides an ion conducting passage. Ion conducting components may becomponents of a composite. Ion conducting components include an ionconducting material, such as a fluoropolymer-based ion conductingmaterial or a hydrocarbon-based ion conducting material. Ion conductingcomponents may also be referred to herein as “electrolytes” or“electrolyte membranes”.

As used herein, an “interface region” refers to a component of acomposite layer that is not electrically conductive. An interface regionmay comprise a material which exhibits negligible ionic conductivity andnegligible electrical conductivity, for example. Interface regions maybe used in conjunction with electron conducting regions to form currentcollectors, and in such cases may be disposed adjacent electronconducting regions on one or both sides of the electron conductingregion. Electron conducting regions may be embedded in an interfaceregion to form a current collector. It is to be understood that aninterface region (or interface regions) is an optional component in acurrent collector, not a necessary component. When used as a componentof a current collector, an interface region may be used to promoteadhesion between electron conducting regions and ion conductingcomponents, and/or may be used to provide electrical insulation betweenadjacent electrochemical cells.

As used herein, “fuel” refers to any material suitable for use as a fuelin a fuel cell. Examples of fuel may include, but are not limited tohydrogen, methanol, ethanol, butane, borohydride compounds such assodium or potassium borohydride, formic acid, ammonia and ammoniaderivatives such as amines and hydrazine, complex metal hydridecompounds such as aluminum borohydride, boranes such as diborane,hydrocarbons such as cyclohexane, carbazoles such as dodecahydro-n-ethylcarbazole, and other saturated cyclic, polycyclic hydrocarbons,saturated amino boranes such as cyclotriborazane.

As used herein, “plane” refers to a two-dimensional hypothetical surfacehaving a determinate extension and spatial direction or position. Forexample, a rectangular block may have a vertical plane and twohorizontal planes, orthogonal to one another. Planes may be definedrelative to one another using angles greater or less than 90 degrees,for example.

As used herein, “fuel cell connection component” refers to a fuel cellinterconnect or a fuel cell current collector, or other connectioncomponent that directly or indirectly creates an electrical pathwayincluding between at least one electrode of the fuel cell and anexternal circuit or that directly or indirectly creates an electricalpathway including between at least one electrode of the fuel cell and atleast one other electrode of the fuel cell.

As used herein, “interconnect” refers to a fuel cell connectioncomponent wherein the interconnect directly or indirectly creates anelectrical pathway including between at least one electrode of the fuelcell and an external circuit. In some embodiments, the interconnect cancreate an electrical pathway between one electrode of the fuel cell andanother electrode of the fuel cell, which can in turn allow current toflow to an external circuit through other connection components;thereby, indirectly creating an electrical pathway between at least oneelectrode of the fuel cell and the external circuit. In someembodiments, an interconnect can be a current collector.

As used herein, “current collector” refers to a fuel cell connectioncomponent wherein the current collector directly or indirectly createsan electrical pathway including between at least one electrode of thefuel cell and at least one other electrode of the fuel cell. In someembodiments, the current collector can create an electrical pathwaybetween one electrode of the fuel cell and an external circuit throughother connection components, which can in turn allow current to flow toanother electrode of the fuel cell through other connection components;thereby, indirectly creating an electrical pathway between at least oneelectrode of the fuel cell and at least one other electrode of the fuelcell. In some embodiments, a current collector can be an interconnect.

As used herein, “binder” refers to a material that can bind or holdmaterials together. For example, a binder can be a non-conductivematerial, such as a polymer or a polymer mixture, and can be curable. Insome embodiments, a binder can be any suitable epoxy or epoxy resin thatcan bind materials together. A binder can be any suitable thermoset orthermoplastic polymer.

A conventional prior art fuel cell stack 10 is shown in FIG. 1A. Fuelcell stack 10 has unit fuel cells 20, which may be arranged in series.Fuel cells 20 may, for example, include proton exchange membrane (PEM)fuel cells. Fuel cells 20 each include a membrane electrode assembly(MEA) 22 having a cathode, an anode, a proton exchange membrane and gasdiffusion layers (not shown). Electrons liberated at the anode travelthrough landings 32 in a separator plate 34 to the cathode in the MEA ofthe next unit cell. Electrons liberated at the anode in the MEA of thelast unit cell travel through connection components 36 to an externalcircuit 38. Electrons travel from a separator plate 34 to a bus plate 40which is connected via a connector 42 to external circuit 38.

FIG. 1B shows a schematic sectional view of the electron flow through aportion 50 of the fuel cell stack of FIG. 1A. The fuel (e.g. hydrogen)travels through first separator plate 34′ through GDL 30A′ and reacts atanode 26′ liberating electrons and protons. Electrons travel throughfirst separator plate 34′ through GDL 30C″ and cathode 24″ of the nextunit cell. Electrons travel through separator plate 34′ in a directionthat is perpendicular to the plane of the separator plate 34′ (orperpendicular to the surfaces that bound its length). The electrons thatare liberated at anode 26″ travel through separator plate 34″ in adirection that is perpendicular to the plane of the plate into bus plate40.

Since the predominant direction of current flow through a separatorplate is through-plane (i.e. perpendicular to the plane of the plate orto the two surfaces with the greatest area), separator plates employedin conventional fuel cell stacks must have high through-plane electricalconductivity. Since electrons travel through the faces of a separatorplate (i.e. through the two surfaces with the greatest area), thesefaces must be electrically conductive. As can be seen, in theconventional fuel cell stack shown, the proton exchange membrane is notin direct physical contact with any of the connection components (i.e.it is not in physical contact with separator plates 34, bus plate 40, orinterconnects 42).

FIG. 2A is a cross-sectional view of an example planar fuel cell layer100, as described in commonly-owned U.S. Pat. No. 7,632,587 entitledELECTROCHEMICAL CELLS HAVING CURRENT-CARRYING STRUCTURES UNDERLYINGELECTROCHEMICAL REACTION LAYERS, the entire teachings of which areincorporated herein by reference. Example planar fuel cell layer 100includes a composite layer 124 having ion conducting components 118 andcurrent collectors 112. In the example fuel cell layer 150 shown in FIG.2B, composite layer 174 also has substrate regions 172. Substrateregions 172 may include a material that is electrically non-conductive,and may also be ionically non-conductive. Returning to FIG. 2A, fuelcell layer 100 may include two types of electrode coatings, namelycathode coatings 116C and anode coatings 116A. Cathode coatings 116C aredisposed on the upper side of composite layer 124 and are adhered to theupper surface of composite layer 124. (Illustrated as 166C and 166A,respectively, in FIG. 2B). Anode coatings 116A are disposed on the lowerside of composite 124 and are adhered to the lower surface of composite124.

Example planar fuel cell layer 100 has three unit fuel cells 120, 121and 122. Each unit cell is bounded by current collectors 112. Currentcollectors 112 include inside current collectors 112 a (e.g., currentcollectors that are located inside fuel cell layer 100 between two unitcells) and interconnects 112 b (e.g., current collectors that arelocated on the ends of fuel cell layer 100). In the example planar fuelcell layer shown, inside current collectors 112 a and interconnects 112b are the same.

FIG. 3A is a schematic perspective diagram of unit fuel cell 120. In theembodiment shown, the fuel and oxidant are respectively, hydrogen andoxygen. However, it is to be understood that embodiments of theinvention may be used with fuel cells utilizing other combinations offuel and oxidant. Hydrogen contacts anode coating 116A and isdissociated into protons and electrons. Electrons travel through anodecoating 116A in a direction that is parallel to the plane of fuel cell120 and into and through current collector 112 a, which is shared withan adjacent unit cell. Electrons travel through current collector 112 ain a direction that is perpendicular to the plane of fuel cell 120, tothe cathode coating of the next unit cell. Protons travel through ionconducting component 118 to the reaction site in cathode 116C.

Unit fuel cell 120 is located on an outside edge of fuel cell layer 100(of FIG. 2A). Electrons travel from an external circuit (not shown)through interconnect 112 b in a direction that is parallel to the length(into the page) of fuel cell 120 and along the length of interconnect112 b and then in a direction that is perpendicular to the plane of fuelcell 120 and into the inactive portion 115 of cathode coating 116C.Inactive portion 115, since it is not in contact with ion conductingcomponent 118, does not support the reaction between the oxidant andprotons, but rather, acts as a connection component. Thus, togetherinactive portion 115 and interconnect 112 b form connection components126. Electrons travel from inactive portion 115 to active portion 117 ofcathode coating 116C in a direction that is parallel to the plane ofboth cathode coating 116C, fuel cell layer 100 and interconnect 112 b.Oxygen contacts cathode coating 116C and travels to the sites ofchemical reaction. Oxygen is reduced and product water is produced,which may either diffuse into the surrounding atmosphere or remain incathode coating 116C.

FIG. 3B is a truncated schematic perspective view of current travelingthrough connection components 126 including an interconnect andoptionally, the inactive portion of an electrode coating. FIGS. 3C and3D are plots of current “i” as a function of distance “d” along length“L” and width “W,” respectively of connection components 126 (width Wmay or may not be the same as the width of interconnect 112 b). Currenttravels from the active portion of the electrode coating through eitherthe inactive portion of the electrode coating or the interconnect in adirection that is parallel to the “y” axis. If the electrode coating hashigher electrical conductivity than the interconnect, the current maytake a route that is predominantly through the inactive portion of theelectrode coating. If the interconnect has a higher electricalconductivity than the electrode coating, the current may take a routethat is predominantly through the interconnect. As shown in FIG. 3C,current that travels in this direction is constant over width W (andaccordingly, the current density is constant along W).

Current also travels throughout the length of interconnect 112 b to theexternal circuit. As shown in FIG. 3D, the current increases along thelength L of interconnect 112 b. Similarly, the current density increasesalong length L to the connection with the external circuit. As can beseen, the distance that a charge travels over length L is significantlylonger than the distance it travels over width W. Since current isaccumulated along the length of an interconnect and current travels arelatively longer distance along the length of an interconnect comparedto across the width if the unit cell, resistivity in interconnects canbe a major source of electrical performance loss. Accordingly, it isdesirable that interconnects 112 b have high conductivity along theirlength L.

There are trade-offs to consider when designing interconnects for planarfuel cell layers. On one hand, it may be desirable for an interconnectto have high electrical conductivity, especially along its length.However, many materials that possess high electrical conductivity areeither expensive or, under oxidative conditions, produce corrosionproducts (e.g. copper ions) which are capable of contaminating activecomponents of the fuel cell (e.g. the ion conducting component).Accordingly, it may be desirable for interconnects to possess highelectrical conductivity and be designed so that they do not exposeactive components of the fuel cell to corrosion products.

In some planar fuel cell layers (e.g. planar fuel cell layer 100) theion conducting components are disposed between the current collectorswith their edges in physical contact with the edges of the currentcollectors. It is desirable for planar fuel cell layers to be resistantto leaks of fuel or oxidant across the fuel cell layer. The currentcollectors (e.g., interconnects) of the embodiments of the presentinvention are capable of forming a leak-resistant bond with thematerials that form the ion conducting components. For example, the bondmay be able to withstand a gas pressure of about 5 psi, or about 15 psi,without leaking a detectable quantity of fluid, such as fuel. In someembodiments, the layer may be substantially impermeable to some fluids,but permeable to others. For example, the layer may be substantiallyimpermeable to a gas pressure imparted by a fuel; however, water may beable to migrate across the ion conducting components.

Some planar fuel cells are designed to power portable consumerapplications, such as notebook computers, cellular telephones, personaldigital assistants (PDAs), and the like. In such applications, the spaceavailable for a fuel cell assembly and system is small. Some planar fuelcells require clamping or compressive force to hold electricalinterconnects in contact with the external circuit. Clamps and othermeans for compression can occupy valuable space in portable consumerdevices. Components of fuel cells (e.g. gas diffusion layers, catalystlayers, flow channels) that are clamped must be able to withstand theclamping force without being deformed or crushed. Additionally, the useof clamps and other compression means can constrain the design andassembly methods of the fuel cell assembly. The planar fuel cells of thepresent embodiments do not require clamping or compressive force inorder for them to remain in contact with an external circuit.

FIGS. 4A-4G show truncated sectional views of interconnects within aunit cell, according to several example embodiments. The electrodecoatings have been omitted for clarity, and only a portion of ionconducting components 202 have been included in the Figures.Interconnects 210, 220, 230, 240, 250, 260, 260 a, 270 each have anelectron conducting component 218, 228, 238, 248, 258, 268, 268 a, 278comprising one or more electron conducting regions of one or more types.Interconnects 210, 230, 250, 260, 260 a, 270 include one or more firstelectron conducting regions 212, 232, 252, 262, 262 a, 272.Interconnects 210, 220, 230, 240, 250, 260, 260 a, 270 include one ormore second conducting regions 214, 224, 234, 244, 254, 264, 264 a, 274.Interconnects 220, 240, 250, 260, 260 a, 270 also include interfaceregions 226, 246, 256, 266, 266 a, 276.

First conducting regions 212, 232, 252, 262, 262 a, 272 may include amaterial that has moderate electrical conductivity and is corrosionresistant. For example, first conducting regions may includecarbonaceous materials, such as carbon fibers, carbon needles, amorphouscarbon, carbon needles, carbon foams, carbon cloth, the like, orcombinations of thereof. First conducting region may, additionally oralternatively, include non-carbonaceous materials such as electricallyconductive ceramics, electrically conductive polymers, the like, orcombinations of these.

In a fuel cell layer, a first conducting region may provide a moderatelyconductive pathway from the electrode coating to the second conductingregion, if present, or vice versa. In an interconnect that includes asecond conducting region, a first conducting region may assist inisolating the active components of the fuel cell from corrosionproducts. In such an interconnect, the second conducting region may bedisposed adjacent to the first conducting region (e.g. FIG. 4A, 4E), ormay be disposed between two portions of, or embedded in, the firstconducting region (e.g. FIG. 4C, 4F, 4G, 4H). In an interconnect thatdoes not include a second conducting region, a first conducting regionmay provide a moderately conductive pathway to or from the externalcircuit.

Second conductive regions 214, 224, 234, 244, 254, 264, 264 a, 274include a material that has very high electrical conductivity (e.g. amaterial that has an electrical conductivity that is higher than theelectrical conductivity of the material(s) in the first conductingregion). For example, a second conducting region may include a metal ora metal alloy. In an example embodiment, the second conducting regionincludes copper, for example, a copper mesh. However, in otherembodiments, the second conducting region may include other materialshaving high electrical conductivity. In a fuel cell layer, a secondconducting region may provide a highly conductive pathway along thelength (or most of the length) of the interconnect to or from theexternal circuit.

Interface regions 226, 246, 256, 266, 266 a, 276 include one or morematerials, which may be electrically non-conductive, ionicallynon-conductive, or both. For example, interface regions, in their curedor uncured form: may function as a binder; be chemically inert; providea good surface for bonding with materials of ion conducting components;or, a combination of these. Interface regions may, alternatively oradditionally, include a non-conductive material that acts as a filler orstrengthener. For example, interface regions may include fiber glass,epoxy, polymers, thermoset polymers, plastic, titanium dioxide, ironoxide, calcium carbonate, the like, or combinations of these.

In a fuel cell layer, interface regions may serve one or more of anumber of functions. Interface regions may assist in isolating unitcells by providing a non-conducting surface for an electrode coating toterminate at. An interface region may provide a surface that is capableof forming moderately strong bonds with ion conducting components.Depending on the materials and method used, interface regions maypromote adhesion between interconnects and the ion conductingmaterial(s) that form ion conducting components. With an interconnectthat includes second electron conducting regions but not first electronconducting regions, interface region may isolate ion conductingcomponents from direct physical contact with second conducting region,thereby reducing the potential for contamination with corrosionproducts.

FIG. 4A shows an interconnect, according to a first example embodiment.Interconnect 210 has an electron conducting component 218 comprising onefirst conducting region 212 and one second conducting region 214. In afuel cell layer, interconnect 210 may provide high electricalconductivity (i.e. via second conducting region 214) while isolatingactive components of the fuel cell from exposure to corrosion products.Since second conducting region 214 is not in direct physical contactwith ion conducting component 202, the potential for corrosion productsto leach or migrate directly into ion conducting component 202 may bereduced. The associated electrode coating may be located so that it isnot in direct physical contact with second electron conducting region214 (e.g. it may extend over or under first conducting region 212 andnot second conducting region 214). In such an embodiment, the potentialfor corrosion products to leach or migrate into the ion conductingcomponent indirectly (e.g. via the inactive portion of the electrodecoating), over the life of the fuel cell system, may be greatly reduced.

FIG. 4B shows an interconnect, according to a second example embodiment.Interconnect 220 has an electron conducting component 228 comprising onesecond electron conducting region 224, and an interface region 226.Since second conducting region 224 is not in direct physical contactwith ion conducting component 202, the potential for corrosion productsto leach directly into conducting component 202 may be reduced.Interface region 226 may provide a surface that promotes adhesionbetween ion conducting component 202 and interconnect 220.

First conducting regions and/or interface regions may also providestrength or stiffness to interconnects. FIGS. 4C and 4D showinterconnects 230 and 240 respectively. Interconnect 230 has one secondconducting region 234 sandwiched between two first conducting regions232. Interconnect 240 has one second conducting region 244 sandwichedbetween two interface regions 246. The inclusion of a first conductingregion 232 or an interface region 246 on either side of secondconducting region 234, 244 may provide additional strength or stiffnessto interconnect 230, 240.

FIG. 4E shows an interconnect, according to a fifth example embodiment.Interconnect 250 has an electron conducting component 258 comprising onefirst conducting region 252 and one second conducting region 254.Interconnect 250 also has one interface region 256. In a fuel celllayer, first conducting region 252 may provide a path from the electrodecoating to second conducting region 254 or vice versa. First conductingregion may enable second conducting region 254 and the electrode coatingto be in electrical contact without being in physical contact, therebyreducing the potential for contamination of ion conducting component 202over the lifetime of the fuel cell system. Second conducting region 254may provide a highly conductive pathway into or out of the unit fuelcell. Interface region 256 may provide a surface that promotes adhesionbetween the material(s) of ion conducting component 202 and interconnect250.

FIGS. 4F and 4G show interconnects, according to sixth and seventhexample embodiments, respectively. Interconnects 260 and 270 are eachvariations on earlier-described embodiments. As can be seen,interconnects 260, 270 each have an electron conducting component 268,278 comprising one second conducting region 264 sandwiched between twofirst conducting regions 262. The regions of interconnects 260, 270 mayfunction similarly to the regions of interconnects according topreviously-discussed embodiments.

FIG. 4H shows an interconnect, according to an eighth exampleembodiment. Interconnect 260 a is a variation on the embodiment ofinterconnect 260 illustrated in FIG. 4F, although such a variation maybe applied to any of the example embodiments where the second conductingregion is sandwiched between two first conducting regions, or betweentwo interface regions. In FIG. 4H, second conducting region 264 a issandwiched between two first conducting regions 262 a in an asymmetricfashion. Such an embodiment may allow for the distance between secondconducting region and the active regions of the fuel cell to bemaximized, with minimal impact on the overall width of interconnect 260a in an embodiment where second conducting region 264 a is embedded orsandwiched between two other materials.

As can be seen, interconnects 230, 240, 270 are each symmetrical abouttheir length—e.g. they each have a second conducting region 234, 244,274 that is sandwiched between two regions or groups of regions that arethe same on each side. In a fuel cell system, interconnects 230, 240,270 may be less likely to bend or warp, since the region(s) on each sideof second conducting region 234, 244, 274 would have the samecoefficient of thermal expansion.

Some fuel cell systems employ fuel that is a liquid (e.g. methanol in adirect methanol fuel cell system) or that is a humidified gas (e.g.humidified hydrogen in a PEM fuel cell system). In fuel cell systemsthat do not employ fuels in the form of a liquid or humidified gas (e.g.PEM fuel cell systems that employ non-humidified hydrogen), waterproduced at the cathode may pool in the fuel plenum. In any such fuelcell systems where water or a liquid is present, the use of aninterconnect including a metal may lead to contamination of the ionconducting components, through leaching of corrosion products into theion conducting component.

FIG. 5 is a cross-sectional view of a fuel cell system 280, illustratinginterconnects (end current collectors) shown in FIG. 4G, according to anexample embodiment. Fuel cell system 280 has a fuel cell layer 282having a composite layer including interconnects 284, cathode coatings286 and anode coatings 288. Interconnects 284 have first conductingregions 283 including a non-corrosive electrically conductive materialand second conducting regions 285 comprising an electrically conductivematerial which may be susceptible to corrosion, such as a metal. In someembodiments, second conducting regions 285 may have a higher electricalconductivity than first conducting regions 283. In some otherembodiments, second conducting regions 285 and/or first conductingregions 283 may have anisotropic conductivity, and may be moreelectrically conductive in one direction than others; for example, firstconductive regions 283 may be more electrically conductive across theirwidth (e.g. across the page, as illustrated in FIG. 5), while secondconductive regions 285 may be more electrically conductive along theirlength (e.g. into the page, as illustrated in FIG. 5). In theillustrated embodiment, fuel cell system 280 includes a fueldistribution manifold 290 coupled with fuel cell layer 282, defining afuel plenum 292. In the embodiment shown, fuel distribution manifold 290is attached to fuel cell layer 282 via spacer 294. However, inalternative embodiments, the fuel distribution manifold 290 may becoupled directly to the fuel cell layer 282, or may be indirectlycoupled to the fuel cell layer 282 using, for example, a flow field orporous layer (not shown) disposed between the fuel cell layer 282 andthe fuel manifold 290. Additional support structures may be disposedbetween the fuel manifold 290 and the fuel cell layer 282, such as thosedescribed in commonly-owned U.S. Patent Application Publication No.2009/0081493, titled FUEL CELL SYSTEMS INCLUDING SPACE-SAVING FLUIDPLENUM AND RELATED METHODS, the disclosure of which is hereinincorporated by reference in its entirety.

In the illustrated embodiment, spacer 294 is disposed so that it coversthe surface of second electron conducting region 285. Although there isan electrical pathway that extends from a cathode coating 286 to firstconducting region 285 (via either first conducting region 283 or theinactive portion of the cathode coating 286), the fuel does not comeinto contact with first conducting region 285 (neither directly norindirectly via cathode coating 286). Accordingly, interconnect 284provides a highly conductive pathway into and out of fuel cell layer 282but does not expose the active components of the fuel cell layer 282 tomaterials which could yield corrosion products during fuel celloperation.

When employed in a fuel cell system, interconnects according toembodiments may simplify connection to an external circuit. FIGS. 6A and6B are top perspective views of fuel cell layers 302, 342 employinginterconnects 306, 346 of FIG. 4G, according to example embodiments.Partial fuel cell system 300, 340 includes a fuel cell layer 302, 342.Fuel cell system 300 also includes connection components 304. The fuelmanifold assembly is omitted for clarity. Fuel cell layer 302, 342 hascathode coatings 314, 354 and anode coatings (not shown) disposed on acomposite layer comprising inner current collectors 305, 345 andinterconnects 306, 346. In the embodiments shown, interconnects 306 a,346 a are partially covered by cathode coating 314, 354, whileinterconnects 306 b, 346 b are illustrated fully exposed (and would bein contact with the anode coatings of the fuel cell layer 302, 342, notshown). In the embodiment shown, interconnects 306 a, 306 b, 346 a, 346b have a second conducting region 316, 356 that includes a metal. Fuelcell layer 302, 342 further include interface regions 318 a, 318 b, 358a, 358 b, which are disposed on either side of inner current collectors305, 345 to provide a region of electrical discontinuity betweenadjacent unit fuel cells.

Employing interconnects 306 a, 306 b, 346 a, 346 b with first conductingregion 316, 356, one is able to use soldering as a method of connectingfuel cell layer 300, 340 with an external circuit. Referring to FIG. 6A,in fuel cell system 300, solder pads 308 are created and are in contactwith second conducting region 316 of interconnects 306 a, 306 b. Solderpads 308 may provide a larger surface for contact with protuberance 310.In the embodiment shown, protuberance 310 is a screw. However, otherprotuberances may be used, such as pins (e.g. spring pins), knobs, studsor the like. Protuberances 310 may be connected to an external circuitthrough a variety of means. In an example embodiment, protuberances 310are in contact with a circuit board.

An external circuit may also be connected directly to the interconnects.Referring to FIG. 6B, in fuel cell system 340, the wires of externalcircuit 350 may be soldered directly onto interconnects 346 a, 346 b atpoints 348 a, 348 b, respectively. Thus, a fuel cell system employinginterconnects according to some embodiments may not require clamps orcompressive force in order to remain in contact with an externalcircuit. Fuel cell systems according to such embodiments may requireless space in a device, for example, a portable consumer application.

In other embodiments, the interconnect itself may provide a convenienttab or surface for connection with the external circuit. For example, ascrew, pin (e.g. a spring-pin) or other protuberance may be placeddirectly in contact with an interconnect, without the need for a solderpad. In other embodiments, interconnects may be placed in contact withthe terminals of an edge-card connector by plugging the fuel cell layerinto the card-edge connector.

Described above are interconnects, according to one or more embodimentsof the invention, employed in the example planar fuel cell of FIG. 2A.However, interconnects may be applied to other example planar fuelcells. For example, interconnects may be applied to many otherembodiments of edge-collected fuel cells, such as those disclosed inU.S. Pat. No. 5,989,741 entitled ELECTROCHEMICAL CELL SYSTEM WITHSIDE-BY-SIDE ARRANGEMENT OF CELLS and U.S. patent application Ser. No.12/153,764 entitled SIDE-BY-SIDE FUEL CELLS and published as U.S. PatentApplication Publication No. US 2008/0299435.

FIG. 7 is a block process diagram of one possible method of preparinginterconnects, such as the interconnects shown in FIGS. 4E-4H, accordingto an example embodiment. In method 400, first electrically conductivematerial 402 and second electrically conductive material 404 aresubjected to a first layering stage 410 to yield a “layered structure”412. Layered structure 412 is subjected to a curing stage 420 to yield apreform 422. Preform 422 may optionally be subjected to a secondlayering stage 430 to yield a coated preform 432 and optionally, coatedpreform 432 is subjected to a second curing stage 440 to yield aninterconnect sheet 442. Interconnect sheet 442 is subjected to a cuttingstage 450 to yield interconnects 452.

Electrically conductive materials 402, 404 are subjected to a layeringstage 410 to yield a “layered structure” 412. Layering stage 410 mayinclude layering one or more first electrically conductive materials 402with one or more second electrically conductive materials 404 to formlayered structure 412. First electrically conductive materials 402 mayinclude one or more materials that have moderate electrical conductivityand are corrosion resistant. For example, first electrically conductivematerials may include carbonaceous materials, such as graphite, expandedgraphite, carbon fibers, carbon needles, amorphous carbon, carbon foams,the like, or combinations of these. In an example embodiment, firstelectrically conductive materials 402 may include carbon fibers, such aswoven carbon fibers. First electrically conductive materials may alsoinclude a non-conductive material, for example, a non-conductivematerial that is capable of binding materials together or that iscurable, such as a thermoset polymer. In an example embodiment, firstelectrically conductive materials 402 may include an epoxy resin. In afurther example embodiment, first electrically conductive materials 402may include carbon fibers and epoxy resin in the form of apre-impregnated woven carbon fiber.

Second electrically conductive materials 404 may include one or morematerials that have very high electrical conductivity (i.e. one or morematerials that have an electrical conductivity that is higher than theelectrical conductivity of first electrically conductive materials 402).For example, second electrically conductive materials 404 may include ametal or a metal alloy. In an example embodiment, second electricallyconductive materials 404 may include copper or a copper mesh. Secondelectrically conductive materials 404 may additionally include anon-conductive material, such as a polymer or a polymer mixture. Secondelectrically conductive material 404 may include a non-conductivematerial that is capable of binding materials together or that iscurable. In an example embodiment, second electrically conductivematerials 404 may include a polymer mixture that includes a resin, suchas an epoxy resin, or any thermoset or thermoplastic polymer, or anyother polymer or composite possessing suitable properties.

Layered structure 412 may be subjected to a curing stage 420 to yield apreform 422. Curing stage 420 may include subjecting layered structure412 to a temperature, a pressure, or both for a period of time. Layeredstructure 412 may be subjected to a pressure, for example, that issufficient to yield a preform 422 of a desired thickness or flatness.

Preform 422 may optionally be subjected to a second layering stage 430to yield a coated preform 432. Second layering stage 430 may includelayering interface materials 434 with preform 422. Interface regionmaterials 434 may include one or more materials that are non-conductiveand are chemically inert (or are capable of being rendered chemicallyinert). In an example embodiment, interface materials 434 may include afiller 436 and a curable polymer mixture 438. Filler 336 may include anon-conductive material that functions to increase the width of theresulting interface region or provide strength or structural support,for example, glass fibers (e.g. woven glass fibers or non-woven glassfibers), plastic (e.g. plastic sheet, plastic particles, woven plasticstrands, or porous plastic) titanium dioxide, iron oxide, silicondioxide, calcium carbonate, the like, or combinations of these. Curablepolymer mixture 438 may include a material or materials that arechemically inert, electrically insulating or provide a good surface forbonding with ion conducting materials. In an example embodiment, curablepolymer mixture 438 may include a non-conductive material that acts asbinder and is capable of being cured. In some embodiments, curing may beaccelerated or activated in the presence of heat, such as a thermosetpolymer. Curable polymer mixture may be curable without the addition ofheat. Curable polymer mixture may include materials such as a resin, ahardener, a flexiblizer, a catalyst or an accelerant. However, theinterface materials of other embodiments may include only one of thesematerials or none of these materials.

Second layering stage 430 may include layering interface materials 434with preform 422 by disposing filler 436 on preform 422 and thenapplying curable polymer mixture 438. Optionally, second layering stagemay include activating the surface of cured preform 422 prior todisposing filler 436. Activation may improve the adhesion between thesurface of cured preform 422 and interface materials 434.

Coated preform 432 if present, may be subjected to a second curing stage440 to yield an interconnect sheet 442. Second curing stage 440 mayinclude subjecting coated preform 432 to a temperature and a pressurefor a period of time. For example, coated preform 432 may be heated at atemperature that is above the temperature at which curable polymermixture cures but is below the temperature at which it decomposes.Coated preform 432 may be subjected to a pressure, for example, apressure that that is sufficient to yield an interface sheet 442 of adesired thickness or flatness. Optionally, second layering stage 430 andsecond curing stage 440 may be repeated when preparing the interconnectsof FIG. 4G.

Interconnect sheet 442 may be subjected to a cutting stage 460 to yieldinterconnects 452. In cutting stage 460, interface sheet 442 (or preform422) may cut to form individual current collectors 452.

Method 400 may be varied to prepare interconnects according to otherembodiments. For example, the first electron conducting region may beomitted to yield interconnects as shown in FIGS. 4B and 4D.

Orientation of Conductive Fibers

Various embodiments of the present invention provide a fuel cellconnection component that includes conductive fibers. Conductive fibersof any suitable composition can be present in any suitable part of thefuel cell connection component, including either or both of a first andsecond electron conducting region. Any suitable number, orientation,type, or spacing of conductive fibers can be used in the fuel cellconnection components of the present invention. For example, theconductive fibers can be bundles. The bundles can include fibers thatare twisted, untwisted, woven, or in any other suitable arrangement. Theconductive fibers can be separate non-bundled fibers. Similarly alignedfibers or bundles of fibers can be spaced such that they are touching,or pressed together. In another embodiment, similarly aligned fibers orbundles of fibers can have any suitable amount or pattern of spacingbetween the fibers or bundles. For example, similarly aligned fibers orbundles can be spaced apart by about 0.0001 mm, 0.001 mm, 0.01 mm, 0.1mm, 1 mm, or by about 10 mm.

Especially when multiple fuel cells are used, such as in a stack orplanar fuel cell system, electrical resistance from components canaccumulate to create a comparatively large internal resistance withinthe array. A large internal resistance can decrease performance of afuel cell system, including a fuel cell system with multiple cells,including a stack or planar fuel cell system. There is a need for fuelcell connection components that are highly conductive, that are strongand durable, and that are simple and inexpensive to produce.

Various embodiments of the present invention provide a fuel cellconnection component, including an interconnect or a current collector.The fuel cell connection component includes conductive fibers orientedat an angle of less than about 90° to at least one electrode in the fuelcell. The fuel cell connection component provides an electricallyconductive pathway from the at least one electrode of the fuel cell toan external circuit or to an electrode of a different fuel cell.Embodiments of the present invention also provide fuel cells thatinclude the fuel cell connection components, including fuel cell layers,and methods of making the same.

One of skill in the art would generally assume that the highestconductivity in a fuel cell connection component using conductive fiberscould be achieved by forming the shortest and most direct conductivepath in that component. In a fuel cell conducting component, this caninvolve arranging a first set of conductive fibers such that they form aright angle with the electrode. However, for example, in someembodiments of the present invention it has been found that by orientingthe conductive fibers such that they form an angle of less than about90° with the electrode or electrode coating, such as for example 45°,conductivity of the fuel cell connection component is higher than thatof a fuel cell connection component with the conductive fibers orientedat about 90° to the electrode or electrode coating.

Further, for one of skill in the art to arrange conductive fibers in afuel cell connecting component to achieve the shortest path, this caninvolve arranging a second set of conductive fibers such that they forman approximate right angle with the first set of conductive fibers (e.g.the first and second set of conductive fibers form a grid), such thatthe second set of conductive fibers are parallel to the length of thefuel cell conducting component. This is especially the case forinterconnects, wherein current can travel along the length of theinterconnect to an external circuit. Such an arrangement can provide anorientation of fibers wherein the fibers are parallel to the plane ofconduction of electrons. However, in another example, surprisingly andunexpectedly, by including a first set of conductive fibers and a secondset of conductive fibers in the fuel cell connection component, both ofwhich form an angle of less than about 90° with the electrode orelectrode coating, such as for example 45°, and each of which forms anapproximately 90° angle with each other (e.g. the first and second setof conductive fibers form a grid), conductivity of the fuel cellconnection component is higher than that of a fuel cell conductingcomponent that includes a first and second set of conductive fibers, oneof which forms an approximately 90° angle with the electrode orelectrode coating, and each of which forms an approximately 90° anglewith one another.

Without being bound to any particular theory of operation, by orientingthe conductive fibers such that they form an angle of less than about90° with the electrode or electrode coating, such as for example 45°,some embodiments of the fuel cell connection component of the presentinvention can exhibit higher conductivity due to a higher exposedsurface area of carbon fibers at the interface with the electrode, e.g.higher interfacial area. In another example, the angle of less thanabout 90° can allow for the surface area of each fiber or bundle offibers at the electrode interface to be greater than if the fiber orbundle of fibers were oriented at approximately 90° with respect to theelectrode or electrode coating; this can be analogous to the crosssection of a cylinder having greater surface area when taken at non-90°angles to the height of the cylinder. In one example, independently ofhigher area per fiber or per bundle, the angle of less than 90° canallow more room for the fiber or bundles of fibers that occur at theelectrode interface. Even though in some embodiments the non-90° angleof the conductive fibers can cause increased resistivity within the fuelcell connection component, the increase in surface area can more thanoffset this loss, and overall the fuel cell connection component canhave greater conductivity within the fuel cell.

In a fuel cell conducting component that includes a first and second setof conductive fibers, the first of which forms an approximately 90°angle with the electrode or electrode coating, and each of which formsan approximately 90° angle with one another, the second set of fibersallows for a direct path for conduction along the length of thecomponent, and the first set of fibers allows for a direct path fromelectrode-to-electrode; however, within the second set of fibers currentmust hop from fiber to fiber to move from electrode-to-electrode, andwithin the first set of fibers current must hop from fiber to fiber tomove parallel to the length of the component, and within both sets offibers, current must hop from the first set of fibers to the second setof fibers to move from an electrode to a direction parallel to thelength of the component, any of which can cause conductive losses. Incontrast, in embodiments that contain a first set of conductive fibersand a second set of conductive fibers in the fuel cell connectioncomponent, both of which form an angle of less than about 90° with theelectrode or electrode coating, such as for example 45°, and each ofwhich forms an approximately 90° angle with each other (e.g. the firstand second set of conductive fibers form a grid), both sets of fiberscan provide conduction pathways both along the length of the componentand from electrode to electrode along individual fibers with lesshopping between fibers. Even though the orientation of fibers at thisangle can mean the total fiber length along which conduction takes placeis longer for both electrode-to-electrode conduction and for conductionparallel to the length of the fuel cell connection component, a greateroverall cross-sectional area of conductive fibers is available forconduction in both the electrode-to-electrode direction and in adirection parallel to the length of the component, which along withincreased interfacial area can help to offset any conductive lossescaused by increased conductive path-length. Some embodiments canoptionally also include fibers running approximately parallel to thelength of the fuel cell connecting component. Some embodiments do notinclude fibers running approximately parallel to the length of the fuelcell connecting component.

Without being bound to any particular theory of operation, by orientingthe conductive fibers such that they form an angle of less than about90° with the electrode or electrode coating, such as for example 45°,some embodiments of the fuel cell connection component of the presentinvention can be more strong and durable, and can have conductive fibersthat are more resistant to being pulled-out, due to a greater length ofthe conductive fibers within the fuel cell connection component, ascompared to the length of conductive fibers that form an approximately90° angle with the electrode or electrode coating. A greater length ofconductive fibers within the fuel cell connection component translatesto a greater surface area of conductive fibers being present within thefuel cell connection component, which means that a larger surface areaof each conductive fiber is in contact with the binder. By increasingthe surface area of fibers in contact with the binder, some embodimentscan have greater binding with the fibers. Greater binding with thefibers can result in increased pull-out resistance for the fibers.Additionally, greater binding with the fibers can result in greaterstrength or durability of the fuel cell connection component. In someembodiments, the greater binding with the fibers can help to convert afiber-pulling force which has a predominantly tensile component into aforce within the fuel cell connection component that has both a tensileand a shear component, thus distributing the force through a greaterarea of the fuel cell connection component. In some embodiments, varyingthe angle the conductive fibers form with the electrode or electrodecoating can vary the degree to which a tensile fiber-pulling force canbe broken into tensile and shear force components within the fuel cellconnection component. In embodiments that include a second set of fibershaving an approximately 90° angle with the first set of fibers, bothsets of fibers can have greater surface area in contact with the binderdue to a less than 90° angle formed with the electrode or electrodecoating. In embodiments that do not have fibers running parallel to thelength of the fuel cell connecting component, any loss of strengthcaused by a lack of fibers running parallel to the length of the fuelcell connecting component can be more than offset by the increase instrength caused by the increased surface area of the fibers that form aless than 90° angle with the electrode or electrode coating. Otherembodiments also have conductive fibers running approximately parallelto the length of the component, in addition to the fibers forming lessthan a 90° angle with the electrode or electrode coating.

In another example, some embodiments the present invention can be madeusing less compressive force than other fuel cell connection components.In some embodiments, the use of a large amount of compressive forceduring manufacture can help to ensure adequately high density of theconductive fibers at the electrode interface. Additionally, in someembodiments, the use of a large amount of compressive force duringmanufacture can help to ensure a low resistance for current pathwaysthat include hopping from fiber to fiber. However, for embodiments thatinclude conductive fibers oriented at less than 90° with respect to theelectrode or electrode coating, and that include higher interfacialsurface area, the use of high compressive forces to achieve higherdensities of conductive fibers at the interface can be less critical. Insome embodiments, the utility of using high compressive forces duringmanufacture can be offset by the higher interfacial surface area due tothe orientation of the fibers, or offset by other advantages, includingless fiber-to-fiber hopping for conduction in particular directions, orincluding greater overall cross-sectional conductive area. Someembodiments that include conductive fibers oriented at less than 90°with respect to the electrode or electrode coating can be made using thesame or greater amount of compressive force as other fuel cellconnection components.

Some embodiments of the fuel cell connection component that includeconductive fibers oriented at less than 90° with respect to theelectrode or electrode coating can have the advantages discussed herein,including higher conductivity, more secure binding of conductive fibers,greater strength, greater durability, or less compressive force neededduring manufacture, without an increase in complexity, price, changes inmaterials, or other substantial changes in manufacturing processes.Modification of the orientation of the conductive fibers, or addition ofconductive fibers that have a different fiber orientation, can be arelatively simple manufacturing protocol which in some embodiments canbe implemented with a minimal increase in manufacturing complexity orcost.

In various embodiments, the present invention provides a fuel cellconnection component. The fuel cell connection component includes anon-conductive interface region. The non-conductive interface region hasa first surface and a second surface. The fuel cell connection componentalso includes an electron conducting component. The electron conductingcomponent has two surfaces and a length that is parallel to the twosurfaces of the electron conducting component. One of the surfaces ofthe electron conducting component is disposed adjacent to the secondsurface of the interface region. The electron conducting componentincludes conductive fibers. The conductive fibers are orientedapproximately parallel to the two surfaces of the electron conductingcomponent. The conductive fibers are adapted to be oriented at an angleof less than about 90° to at least one electrode in a fuel cell. Thefuel cell connection component also includes a binder. The binder holdsthe interface region and the electron conducting component together. Thefuel cell connection component is adapted for use in the fuel cell suchthat it provides an electrically conductive path between the at leastone electrode of the fuel cell and an external circuit or between the atleast one electrode of the fuel cell and at least one electrode of adifferent fuel cell.

In some embodiments, the conductive fibers that are adapted to beoriented at an angle of less than about 90° to at least one electrode ina fuel cell can include conductive fibers adapted to be oriented at lessthan an angle of about 80°, 70°, 60°, or less than about 50° to the atleast one electrode in the fuel cell. In some embodiments, theconductive fibers that are adapted to be oriented at an angle of lessthan about 90° to at least one electrode in a fuel cell can includeconductive fibers adapted to be oriented at an angle of more than about0°, 10°, 20°, 30° or 40° to the at least one electrode in the fuel cell.In some embodiments, the conductive fibers that are adapted to beoriented at an angle of less than about 90° to at least one electrode ina fuel cell can include conductive fibers adapted to be oriented atabout 45° to the at least one electrode, or at about 40° to about 50° tothe at least one electrode, or at about 35° to about 55° to the at leastone electrode, or at about 30° to about 60° to the at least oneelectrode, or about 22° to about 68° to the at least one electrode. Thefuel cell connection component can include other conductive fibers asidefrom the conductive fibers that are adapted to be oriented at an angleof less than about 90° to the at least one electrode, for exampleconductive fibers that are adapted to be oriented at angles of about 90°to the at least one electrode, or conductive fibers that are adapted tobe oriented at angles of about 0° to the at least one electrode.

In some embodiments, the fuel cell connection component can include atleast a first set of conductive fibers and a second set of conductivefibers. Both the first and second set of conductive fibers can beadapted to be oriented at an angle of less than about 90° to the atleast one electrode in the fuel cell. The first set of conductive fibersand the second set of conductive fibers can be oriented such that thefirst set of conductive fibers forms an angle of between approximately45° and about 135° with the second set of conductive fibers. In someembodiments, the first set of conductive fibers and the second set ofconductive fibers can be oriented such that the first set of conductivefibers forms an angle of between approximately 50° and about 130°,between about 60° and about 120°, between about 70° and about 110°,between about 80° and about 100°, between about 85° and about 95°, or ofabout 90° with the second set of conductive fibers. In some embodiments,the first and second set of fibers form a grid, wherein the fibers ofthe grid form an approximately 45° angle with the at least one electrodeof the fuel cell. In some embodiments, the conductive fibers can includecarbon fibers. In some embodiments, the conductive fibers can includemetal fibers, for example including copper fibers, such as a coppermetal fiber, or such as a composite fiber that includes copper metal andcarbon fibers.

In some embodiments, the fuel cell connection component can include aninterface region that can include glass fibers, and an electronconducting component that can include conductive fibers, and a binder.In some embodiments, the conductive fibers can include fibers such ascarbon fibers or such as fibers including a conductive metal. In someembodiments, the conductive fibers can include conductive metal fibers,such as copper metal fibers, or such as a composite fiber that includesmetal, such as a composite fiber including copper and carbon fibers. Insome embodiments, the electron conducting component can include bothcarbon fibers and fibers that include a conductive metal, such as coppermetal fibers, or such as a composite fiber including copper metal andcarbon fiber. In some embodiments, the electron conducting component caninclude carbon fibers adjacent to the interface region, and fibersincluding conductive metal or a composite thereof adjacent to the carbonfiber region. Either one or both of the carbon and metal or compositefibers can include fibers oriented at less than about 90° to the atleast one electrode of the fuel cell, for example, 45°. Either one orboth of the carbon fibers and the fibers including a conductive metalcan include a first and second set of conductive fibers, each of whichis oriented at less than about 90° to the at least one electrode of thefuel cell, for example, 45°, and wherein the first and second set ofconductive fibers forms an angle of between approximately 45° and about135° with each other, for example 90°. In one example, for either one orboth of the carbon fibers and the fibers including a conductive metal,the first and second set of fibers form a grid, wherein the fibers ofthe grid form an approximately 45° angle with the at least one electrodeof the fuel cell.

In some embodiments, the fuel cell connection component is aninterconnect. In some embodiments, the fuel cell connection component isa current collector. In some embodiments, the fuel call connectioncomponent is both a current collector and an interconnect.

The present invention provides a fuel cell. The fuel cell includes anion conducting component. The fuel cell also includes two or moreelectrode coatings. The fuel cell also includes one or more fuel cellconnection components. The fuel cell connection components include anon-conductive interface region. The non-conductive interface region hasa first surface and a second surface. The first surface of thenon-conductive interface region is in contact with the ion conductingcomponent. The fuel cell connection components also include an electronconducting component. The electron conducting component has two surfacesand a length that is parallel to the two surfaces of the electronconducting component. One of the surfaces of the electron conductingcomponent is disposed adjacent to the second surface of the interfaceregion. The electron conducting component includes conductive fibers.The conductive fibers are oriented approximately parallel to the twosurfaces of the electron conducting component. The conductive fibers areoriented at an angle of less than about 90° to one of the electrodecoatings. The electron conducting component provides an electricallyconductive pathway between the one electrode coating and an externalcircuit or between the one electrode coating and an electrode coating ofanother fuel cell. The pathway extends along the length of the electronconducting component. The fuel cell can include any fuel cell connectioncomponent described herein.

The present invention provides a fuel cell layer. The fuel cell layerincludes a composite layer. The composite layer includes a first surfaceand a second surface. The composite layer includes a plurality of fuelcell connection components. The composite layer includes a plurality ofion conducting components. The ion conducting components are positionedbetween the fuel cell connection components. The composite layer alsoincludes a first plurality of electrode coatings. The first plurality ofelectrode coatings are disposed on the first surface to form anodes. Thecomposite layer also includes a second plurality of electrode coatings.The second plurality of electrode coatings is disposed on the secondsurface to form cathodes. Each of the first and second plurality ofelectrode coating is in ionic contact with one of the ion conductingcomponents and in electrical contact with one of the fuel cellconnection components. At least one of the fuel cell connectioncomponents includes an interface region. The interface region has afirst surface and a second surface. The first surface is in contact withone of the ion conducting components. The at least one fuel cellconnection component also includes at least one electron conductingcomponent. The at least one electron conducting component has twosurfaces and a length parallel to the two surfaces. One of the surfacesof the at least one electron conducting component is disposed adjacentto the second surface of the interface region. The at least one electronconducting component includes conductive fibers. The conductive fibersare oriented approximately parallel to the two surfaces of the at leastone electron conducting component. The conductive fibers are oriented atan angle of less than about 90° to at least one of the first or secondplurality of electrode coatings. At least one of the fuel cellconnection components provides an electrically conductive pathwaysbetween the at least one of the first or second plurality of electrodecoatings and an external circuit or between one of the first or secondplurality of electrode coatings and a different one of the first orsecond plurality of electrode coatings. The pathway extends along thelength of the at least one electron conducting component. The fuel celllayer can include any fuel cell connection component or any fuel celldescribed herein.

FIG. 8A is a top view of fuel cell connection component, in accordancewith various embodiments. FIG. 8A shows a photograph of a top view of acurrent collector with 90° fiber orientation, taken through a low power(<200 magnification) microscope. FIG. 8A shows a fuel cell connectioncomponent that includes a first set and a second set of conductivefibers, the first set of fibers being adapted to be aligned atapproximately a 90° angle with an electrode or an electrode coating, thesecond set of fibers being oriented approximately parallel with thelength of the fuel cell connection component, wherein the first andsecond set of fiber form an approximately 90° angle with one another.Regions of different fiber orientation can be seen, with a relativelylow proportion of cut fibers being exposed to the surface that willeventually be covered with the electrode coating. In FIG. 8A, it can beseen that one set of fibers bundles has exposed ends and the other setof fiber bundles is lying in the plane of the Figure.

FIG. 8B is a side view of a fuel cell connection component, inaccordance with various embodiments. FIG. 8B shows a fuel cellconnection component that includes a first set and a second set ofconductive fibers, the first set of fibers being adapted to be alignedat approximately a 90° angle with an electrode or an electrode coating,the second set of fibers being oriented approximately parallel with thelength of the fuel cell connection component, wherein the first andsecond set of fiber form an approximately 90° angle with one another.FIG. 8B is a photograph of a current collector that has beencross-sectioned to expose the fiber bundles. In FIG. 8B, it can be seenthat one set of fibers has the shortest possible conductive path fromthe top to the bottom surface (visible as vertical cross-sections offibers), whereas the second set of fibers do not form a conductive pathfrom the top to the bottom surface (visible as the ends of fibersrunning parallel to the length of the component); thus, fiber to fiberhopping must occur for current to move through the plane, and fiber tofiber hopping must occur between the second set of fibers for current tomove from the top surface to the bottom surface within the second set offibers.

FIG. 9 shows photographs of low power (<200 magnification) microscopeviews of a current collector with a 45° fiber orientation. FIG. 9A istop view of a fuel cell connection component, in accordance with variousembodiments. FIG. 9A shows a fuel cell connection component thatincludes a first set and a second set of conductive fibers, the firstand second set of fibers being adapted to be oriented at approximately45° to the electrode or electrode coating of the fuel cell, and thefirst and second set of fibers forming an approximately 90° angle withone another. In FIG. 9A, it can be seen that since both the first andsecond set of fibers can contact the electrode and forms anapproximately 45° angle therewith, approximately double the number offibers contacts the top surface, as compared to the embodiment shown inFIG. 8A.

FIG. 9B is a side view of a fuel cell connection component, inaccordance with various embodiments. FIG. 9B shows a fuel cellconnection component that includes a first set and a second set ofconductive fibers, the first and second set of fibers being adapted tobe oriented at approximately 45° to the electrode or electrode coatingof the fuel cell, and the first and second set of fibers forming anapproximately 90° angle with one another. In FIG. 9B, it can be seenthat no fibers form an approximately 90° angle with the electrode (whichwould appear as vertical cross-sections of fibers running top tobottom), and rather all fibers form an approximately 45° angle with theelectrode (visible as ends of fibers).

EXAMPLES

The present invention can be better understood by reference to thefollowing examples which are offered by way of illustration. The presentinvention is not limited to the examples given herein.

Example 1 Voltage Drop Testing of Fuel Cell Connection Components withVarious Orientations of Conductive Fibers

Several fuel cell connection components were prepared with variousorientations of conductive fibers. The fuel cell connection componentseach included a grid of conductive fibers between two layers of glassfibers, bound together by an epoxy resin. The fuel cell connectioncomponents included two fuel cell connection components with 8 bundlesof carbon fibers in a “standard” configuration (“8× Standard CC,” 4adapted to be at approximately 90° to the electrode or electrodecoating, and 4 running approximately parallel to the length of the fuelcell connection component), two fuel cell connection components with 8bundles of carbon fibers in a 45° configuration (“8×45° CC,” all 8adapted to be at approximately 45° to the electrode or electrodecoating, with 4 forming an approximately 90° with the other four), onefuel cell connection component with 12 bundles of carbon fibers in a“standard” configuration (“12× Standard CC,” 6 adapted to be atapproximately 90° to the electrode or electrode coating, and 6 runningapproximately parallel to the length of the fuel cell connectioncomponent), and one fuel cell connection component with 12 bundles ofcarbon fibers in a 45° configuration (“12×45° CC,” all 12 adapted to beat approximately 45° to the electrode or electrode coating, with 6forming an approximately 90° with the other 6). The resistance of eachfuel cell connection component was measured by compressing the fuel cellconnection component between two electrodes using approximately 10 psipressure, passing a known current through the component, and measuringthe voltage drop using a DC resistance analyzer. A greater voltage dropcorresponds to a higher resistance. Next, the voltage drop of each fuelcell connection component was measured in the same fashion, but using aGrafoil™ pad (5 mil, made from graphite flake) on top. Since theGrafoil™ pad generally has less contact resistance with the fuel cellconnection component regardless of the interfacial surface area betweenthe fuel cell connection component and the pad, measuring the voltagedrop across the component using the Grafoil™ pad can help to distinguishresistance caused by contact resistance between the component and theelectrode versus the bulk resistance of the component. As can be seenfrom the results reported below in Table 1, the 45° configuration cancause between an about 20% to about 26% improvement over the “standard”configuration. Additionally, the smaller measured differences inresistance between the 90° configuration and the 45° configuration asmeasured when using the Grafoil™ pad as compared to the largerdifferences when measured without the Grafoil™ pad is evidence that, inthese embodiments, the 45° configuration has a lower contact resistance(e.g. increased interfacial area) than the 90° configuration, and thatthe 45° configuration has a lower bulk resistance than the 90°configuration, but that the difference between the contact resistance ofthe 45° configuration and the 90° configuration is greater than thedifference between the bulk resistance of the 45° configuration and the90° configuration.

TABLE 1 mV drop at 0.5 A with Sample mV drop at 0.5 A Grafoil ™ pad ontop  8 × Standard CC 22 7.2  8 × Standard CC 21.5 7.3  8 × 45° CC 9.45.2  8 × 45° CC 13.8 5.5 12 × Standard CC 34 3.3 12 × 45° CC 17 1.3

The above description is intended to be illustrative, and notrestrictive. Other embodiments can be used, such as by one of ordinaryskill in the art upon reviewing the above description. Also, in theabove Detailed Description, various features may be grouped together tostreamline the disclosure. This should not be interpreted as intendingthat an unclaimed disclosed feature is essential to any claim. Rather,inventive subject matter may lie in less than all features of aparticular disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment. The scope of the invention should bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow thereader to quickly ascertain the nature of the technical disclosure. Itis submitted with the understanding that it will not be used tointerpret or limit the scope or meaning of the claims.

Additional Embodiments

The present invention provides for the following exemplary embodiments,the numbering of which is not to be construed as designating levels ofimportance:

Embodiment 1 provides a fuel cell connection component, including: anon-conductive interface region having a first surface and a secondsurface; an electron conducting component having two surfaces and alength that is parallel to the two surfaces of the electron conductingcomponent, wherein one of the surfaces of the electron conductingcomponent is disposed adjacent to the second surface of the interfaceregion, the electron conducting component including conductive fibersoriented approximately parallel to the two surfaces of the electronconducting component and adapted to be oriented at an angle of less thanabout 90° to at least one electrode in a fuel cell; and a binder,wherein the binder holds the interface region and the electronconducting component together; wherein the fuel cell connectioncomponent is adapted for use in the fuel cell such that it provides anelectrically conductive pathway between the at least one electrode ofthe fuel cell and an external circuit or between the at least oneelectrode of the fuel cell and at least one electrode of a differentfuel cell, said path extending along the length of the electronconducting component.

Embodiment 2 provides the fuel cell connection component of Embodiment1, wherein the conductive fibers are adapted to be oriented at an angleof between about 22° and about 68° to the at least one electrode of thefuel cell.

Embodiment 3 provides the fuel cell connection component of any one ofEmbodiments 1-2, wherein the conductive fibers are adapted to beoriented at an angle of about 45° to the one electrode of the fuel cell.

Embodiment 4 provides the fuel cell connection component of any one ofEmbodiments 1-3, wherein the conductive fibers include at least a firstset of conductive fibers and a second set of conductive fibers, whereinboth the first and second set of conductive fibers are adapted to beoriented at an angle of less than about 90° to the at least oneelectrode in the fuel cell, wherein the first set of conductive fibersand the second set of conductive fibers are oriented such that the firstset of conductive fibers forms an angle of approximately 45° to about135° with the second set of conductive fibers.

Embodiment 5 provides the fuel cell connection component of any one ofEmbodiments 1-4, wherein the conductive fibers include at least a firstset of conductive fibers and a second set of conductive fibers, whereinboth the first and second set of conductive fibers are adapted to beoriented at an angle of less than about 90° to the at least oneelectrode in the fuel cell, wherein the first set of conductive fibersand the second set of conductive fibers are oriented such that the firstset of conductive fibers forms an angle of approximately 90° with thesecond set of conductive fibers.

Embodiment 6 provides the fuel cell connection component of any one ofEmbodiments 1-5, wherein the binder includes an adhesive selected froman epoxy or a resin.

Embodiment 7 provides the fuel cell connection component of any one ofEmbodiments 1-6, wherein the interface region includes glass fibers.

Embodiment 8 provides the fuel cell connection component of any one ofEmbodiments 1-7, wherein the fuel cell connection component includes acurrent collector, wherein the current collector is adapted for use inthe fuel cell such that it provides an electrically conductive pathbetween the at least one electrode of the fuel cell and at least oneelectrode of a different fuel cell.

Embodiment 9 provides the fuel cell connection component of any one ofEmbodiments 1-8, wherein the electron conducting component includes afirst electrically conductive material, wherein the first electricallyconductive material includes the conductive fibers.

Embodiment 10 provides the fuel cell connection component of any one ofEmbodiments 1-9, wherein the conductive fibers include carbon fibers.

Embodiment 11 provides the fuel cell connection component of any one ofEmbodiments 1-10, wherein the fuel cell connection component includes aninterconnect, wherein the interconnect is adapted for use in the fuelcell such that it provides an electrically conductive path between theat least one electrode of the fuel cell and an external circuit.

Embodiment 12 provides the fuel cell connection component of any one ofEmbodiments 1-11, wherein the electron conducting component includes twoelectron conducting regions, each electron conducting region beingdefined between two surfaces parallel to the length of the electronconducting component.

Embodiment 13 provides the fuel cell connection component of any one ofEmbodiments 1-12, wherein: the electron conducting component includes afirst electron conducting region including a first electricallyconductive material, and a second electron conducting region including asecond electrically conductive material; and wherein the firstelectrically conductive material is corrosion-resistant and theconductivity of the second electrically conductive material is greaterthan the conductivity of the second electrically conductive material.

Embodiment 14 provides the fuel cell connection component of Embodiment13, wherein the second electrically conductive material is selected fromthe group consisting of a metal, a metal alloy, and combinationsthereof.

Embodiment 15 provides the fuel cell connection component of any one ofEmbodiments 13-14, wherein the second electrically conductive materialincludes conductive fibers oriented approximately parallel to the twosurfaces of the electron conducting component and adapted to be orientedat an angle of less than about 90° to one of the electrode coatings ofthe fuel cell.

Embodiment 16 provides the fuel cell connection component of Embodiment15, wherein the conductive fibers of the second electrically conductivematerial include copper metal fibers.

Embodiment 17 provides the fuel cell connection component of any one ofEmbodiments 13-16, wherein the first electrically conductive materialincludes conductive fibers oriented approximately parallel to the twosurfaces of the electron conducting component and adapted to be orientedat an angle of less than about 90° to the one of the electrode coatingsof the fuel cell.

Embodiment 18 provides the fuel cell connection component of Embodiment17, wherein the conductive fibers of the first electrically conductivematerial include carbon fibers.

Embodiment 19 provides the fuel cell connection component of any one ofEmbodiments 13-18, wherein the electron conducting component includestwo first electron conducting regions.

Embodiment 20 provides the fuel cell connection component of any one ofEmbodiments 13-19, wherein the electron conducting component and theinterface region are bonded together to form a composite.

Embodiment 21 provides the fuel cell connection component of any one ofEmbodiments 13-20, further including a third electron conducting regionthat includes the first electrically conductive material.

Embodiment 22 provides the fuel cell connection component of Embodiment21, wherein the first electron conducting region is disposed on a firstside of the second electron conducting region and the third electronconducting region is disposed on a second side of the second electronconducting region and the first and second sides of the second electronconducting region are opposite relative to one another.

Embodiment 23 provides the fuel cell connection component of any one ofEmbodiments 1-22, wherein the interface region is adapted to be incontact with an ion conducting component of the fuel cell.

Embodiment 24 provides a fuel cell, including: an ion conductingcomponent; two or more electrode coatings; and one or more fuel cellconnection components, the fuel cell connection components including anon-conductive interface region having a first surface and a secondsurface, in which the first surface of the non-conductive interface isin contact with the ion conducting component; an electron conductingcomponent having two surfaces and a length that is parallel to the twosurfaces of the electron conducting component, wherein one of thesurfaces of the electron conducting component is disposed adjacent tothe second surface of the interface region, the electron conductingcomponent including conductive fibers oriented approximately parallel tothe two surfaces of the electron conducting component and oriented at anangle of less than about 90° to one of the electrode coatings; whereinthe electron conducting component provides an electrically conductivepathway between the one electrode coating and an external circuit orbetween the one electrode coating and an electrode coating of anotherfuel cell, said pathway extending along the length of the electronconducting component.

Embodiment 25 provides the fuel cell of Embodiment 24, wherein theconductive fibers are oriented at an angle of between about 22° andabout 68° to the one of the electrode coatings.

Embodiment 26 provides the fuel cell of any one of Embodiments 24-25,wherein the conductive fibers include at least a first set of conductivefibers and a second set of conductive fibers, wherein both the first andsecond set of conductive fibers are oriented at an angle of less thanabout 90° to the at least one electrode in the fuel cell, wherein thefirst set of conductive fibers and the second set of conductive fibersare oriented such that the first set of conductive fibers forms an angleof between approximately 45° and about 135° with the second set ofconductive fibers.

Embodiment 27 provides the fuel cell of any one of Embodiments 24-26,wherein the fuel cell connection component includes a current collector,wherein the fuel cell connection component provides an electricallyconductive pathway between the one electrode coating and the electrodecoating of another fuel cell.

Embodiment 28 provides the fuel cell of any one of Embodiments 24-27,wherein the electron conducting component includes a first electricallyconductive material, wherein the first electrically conductive materialincludes the conductive fibers.

Embodiment 29 provides the fuel cell of any one of Embodiments 24-28,wherein the fuel cell connection component includes an interconnect,wherein the fuel cell connection component provides an electricallyconductive pathway between the one electrode coating and an externalcircuit

Embodiment 30 provides the fuel cell of any one of Embodiments 24-29,wherein the electron conducting component includes two electronconducting regions, each electron conducting region being definedbetween two surfaces parallel to the length of the electron conductingcomponent.

Embodiment 31 provides the fuel cell of any one of Embodiments 24-30,wherein: the electron conducting component includes a first electronconducting region including a first electrically conductive materialincluding conductive fibers oriented approximately parallel to the twosurfaces of the electron conducting component and oriented at an angleof less than about 90° to the one of the electrode coatings, and asecond electron conducting region including a second electricallyconductive material including conductive fibers oriented approximatelyparallel to the two surfaces of the electron conducting component andoriented at an angle of less than about 90° to one of the electrodecoatings; and wherein the first electrically conductive material iscorrosion-resistant and the conductivity of the second electricallyconductive material is greater than the conductivity of the secondelectrically conductive material.

Embodiment 32 provides the fuel cell of Embodiment 31, wherein thesecond electrically conductive material is selected from the groupconsisting of a metal, a metal alloy, and combinations thereof.

Embodiment 33 provides the fuel cell of any one of Embodiments 31-32,wherein the conductive fibers of the second electrically conductivematerial include copper metal fibers.

Embodiment 34 provides the fuel cell of any one of Embodiments 31-33,wherein the conductive fibers of the first electrically conductivematerial include carbon fibers.

Embodiment 35 provides a fuel cell layer, including: a composite layerhaving a first surface and a second surface, the composite layerincluding a plurality of fuel cell connection components; and aplurality of ion conducting components, positioned between the fuel cellconnection components; a first plurality of electrode coatings disposedon the first surface to form anodes; and a second plurality of electrodecoatings disposed on the second surface to form cathodes, each of thefirst and second plurality of electrode coatings in ionic contact withone of the ion conducting components and in electrical contact with oneof the fuel cell connection components; wherein at least one of the fuelcell connection components includes an interface region having a firstsurface and a second surface, the first surface in contact with one ofthe ion conducting components; and at least one electron conductingcomponent having two surfaces and a length parallel to the two surfaces,one of the surfaces of the at least one electron conducting componentdisposed adjacent to the second surface of the interface region, whereinthe at least one electron conducting component includes conductivefibers oriented approximately parallel to the two surfaces of the atleast one electron conducting component and oriented at an angle of lessthan about 90° to at least one of the first or second plurality ofelectrode coatings; wherein the at least one of the fuel cell connectioncomponents provides an electrically conductive pathway between the atleast one of the first or second plurality of electrode coatings and anexternal circuit or between the at least one of the first or secondplurality of electrode coatings and a different one of the first orsecond plurality of electrode coatings, said pathway extending along thelength of the at least one electron conducting component.

Embodiment 36 provides the fuel cell connection component of Embodiment35, wherein the conductive fibers include at least a first set ofconductive fibers and a second set of conductive fibers, wherein boththe first and second set of conductive fibers are oriented at an angleof less than about 90° to the at least one electrode in the fuel cell,wherein the first set of conductive fibers and the second set ofconductive fibers are oriented such that the first set of conductivefibers forms an angle of between approximately 45° and about 135° withthe second set of conductive fibers.

Embodiment 37 provides the fuel cell layer of any one of Embodiments35-36, wherein the conductive fibers include carbon fibers.

Embodiment 38 provides the fuel cell layer of any one of Embodiments35-37, wherein at least one of the electron conducting componentsincludes at least two electron conducting materials, including a firstelectron conducting material and a second electron conducting material.

Embodiment 39 provides the fuel cell layer of Embodiment 38, wherein thefirst electron conducting material is substantially corrosion resistant,and wherein the second electron conducting material has an electricalconductivity greater than that of the first electron conductingmaterial.

Embodiment 40 provides the fuel cell layer of any one of Embodiments38-39, wherein the first electron conducting material includes carbonfibers, wherein the second electron conducting material includes copperfibers.

Embodiment 41 provides the fuel cell layer of any one of Embodiments39-40, wherein the first electron conducting material is in electricalcontact with one of the first or the second plurality of electrodecoatings.

Embodiment 42 provides the fuel cell layer of Embodiment 41, wherein thesecond electron conducting material is in electrical contact with boththe first electron conducting material and the external circuit,providing the electrically conductive pathway between the electrodecoating and the external circuit.

Embodiment 43 provides the apparatus or method of any one or anycombination of Embodiments 1-42 optionally configured such that allelements or options recited are available to use or select from.

What is claimed, is:
 1. A fuel cell connection component, comprising: anelectrically non-conductive interface region having a first surface anda second surface, the first and second surface of the interface regionbeing parallel to an x-z plane, the x-z plane having an x-y planeperpendicular thereto; an electron conducting component having twosurfaces parallel to the x-z plane and a length that is parallel to thex-z plane, wherein one of the surfaces of the electron conductingcomponent is disposed adjacent to the second surface of the interfaceregion, the electron conducting component comprising conductive fibersoriented parallel to the x-z plane and configured to be oriented at anangle of greater than 0° and less than 90° to a first or second surfaceof at least one electrode in a fuel cell, wherein the first and secondsurface of the electrode are parallel to the x-y plane, the first andsecond surfaces of the electrode being the largest two surfaces of theelectrode; and a binder, wherein the binder holds the interface regionand the electron conducting component together; wherein the fuel cellconnection component is configured for use in the fuel cell such that itprovides an electrically conductive pathway between the at least oneelectrode of the fuel cell and an external circuit or between the atleast one electrode of the fuel cell and at least one electrode of adifferent fuel cell, said path extending along the length of theelectron conducting component.
 2. The fuel cell connection component ofclaim 1, wherein the conductive fibers are configured to be oriented atan angle of between 22° and 68° to the first or second surface of the atleast one electrode.
 3. The fuel cell connection component of claim 1,wherein the conductive fibers are configured to be oriented at an angleof 45° to the first or second surface of the at least one electrode. 4.The fuel cell connection component of claim 1, wherein the conductivefibers comprise at least a first set of conductive fibers and a secondset of conductive fibers, wherein both the first and second set ofconductive fibers are configured to be oriented at an angle of less than90° to the first or second surface of the at least one electrode in thefuel cell, wherein the first set of conductive fibers and the second setof conductive fibers are oriented such that the first set of conductivefibers forms an angle of 45° to 135° with the second set of conductivefibers.
 5. The fuel cell connection component of claim 1, wherein theconductive fibers comprise at least a first set of conductive fibers anda second set of conductive fibers, wherein both the first and second setof conductive fibers are configured to be oriented at an angle of lessthan 90° to the first or second surface of the at least one electrode inthe fuel cell, wherein the first set of conductive fibers and the secondset of conductive fibers are oriented such that the first set ofconductive fibers forms an angle of 90° with the second set ofconductive fibers.
 6. The fuel cell connection component of claim 1,wherein the binder comprises an adhesive selected from an epoxy or aresin.
 7. The fuel cell connection component of claim 1, wherein theinterface region comprises glass fibers.
 8. The fuel cell connectioncomponent of claim 1, wherein the fuel cell connection componentcomprises a current collector, wherein the current collector isconfigured for use in the fuel cell such that it provides anelectrically conductive path between the at least one electrode of thefuel cell and at least one electrode of a different fuel cell.
 9. Thefuel cell connection component of claim 1, wherein the electronconducting component comprises a first electrically conductive material,wherein the first electrically conductive material comprises theconductive fibers.
 10. The fuel cell connection component of claim 1,wherein the conductive fibers comprise carbon fibers.
 11. The fuel cellconnection component of claim 1, wherein the fuel cell connectioncomponent comprises an interconnect, wherein the interconnect isconfigured for use in the fuel cell such that it provides anelectrically conductive path between the at least one electrode of thefuel cell and an external circuit.
 12. The fuel cell connectioncomponent of claim 1 wherein the electron conducting component comprisestwo electron conducting regions, each electron conducting region beingdefined between two surfaces parallel to the length of the electronconducting component.
 13. The fuel cell connection component of claim 1,wherein: the electron conducting component comprises a first electronconducting region comprising a first electrically conductive material,and a second electron conducting region comprising a second electricallyconductive material; and wherein the first electrically conductivematerial is corrosion-resistant and the conductivity of the secondelectrically conductive material is greater than the conductivity of thesecond electrically conductive material.
 14. The fuel cell connectioncomponent of claim 13, wherein the second electrically conductivematerial comprises a metal, a metal alloy, or combinations thereof. 15.The fuel cell connection component of claim 13, wherein the secondelectrically conductive material comprises conductive fibers orientedparallel to the x-z plane and configured to be oriented at an angle ofless than 90° to the first or second surface of the at least oneelectrode.
 16. The fuel cell connection component of claim 15, whereinthe conductive fibers of the second electrically conductive materialcomprise copper metal fibers.
 17. The fuel cell connection component ofclaim 13, wherein the first electrically conductive material comprisesconductive fibers oriented parallel to the x-z and configured to beoriented at an angle of less than 90° to the first or second surface ofthe at least one electrode.
 18. The fuel cell connection component ofclaim 17, wherein the conductive fibers of the first electricallyconductive material comprise carbon fibers.
 19. The fuel cell connectioncomponent of claim 1, wherein the interface region is configured to bein contact with an ion conducting component of the fuel cell.
 20. A fuelcell, comprising: an ion conducting component; two or more electrodecoatings, each electrode coating independently comprising a firstsurface and a second surface, wherein the first and second surface ofthe electrode coatings are parallel to an x-y plane, the x-y planehaving an x-z plane perpendicular thereto, the first and second surfacesbeing the largest two surfaces of each of the electrode coatings; andone or more fuel cell connection components, the fuel cell connectioncomponents comprising an electrically, non-conductive interface regionhaving a first surface and a second surface, the first and secondsurface of the interface region being parallel to the x-z plane, inwhich the first surface of the non-conductive interface is in contactwith the ion conducting component; an electron conducting componenthaving two surfaces parallel to the x-z plane and a length that isparallel to the x-z plane, wherein one of the surfaces of the electronconducting component is disposed adjacent to the second surface of theinterface region, the electron conducting component comprisingconductive fibers oriented parallel to the x-z plane and oriented at anangle of greater than 0° and less than 90° to the first or secondsurface of one of the electrode coatings; wherein the electronconducting component provides an electrically conductive pathway betweenthe one electrode coating and an external circuit or between the oneelectrode coating and an electrode coating of another fuel cell, saidpathway extending along the length of the electron conducting component.21. A fuel cell layer, comprising: a composite layer having a firstsurface and a second surface, the composite layer comprising a pluralityof fuel cell connection components; and a plurality of ion conductingcomponents, positioned between the fuel cell connection components; afirst plurality of electrode coatings disposed on the first surface toform anodes; and a second plurality of electrode coatings disposed onthe second surface to form cathodes, each of the first and secondplurality of electrode coatings in ionic contact with one of the ionconducting components and in electrical contact with one of the fuelcell connection components, each of the first and second plurality ofelectrode coatings independently comprising a first surface and a secondsurface, each of the first and second surfaces of the electrode coatingsbeing parallel to an x-y plane, the x-y plane having an x-z planeperpendicular thereto, the first and second major surfaces of theelectrode coatings being the largest two surfaces of each of theelectrode coatings: wherein at least one of the fuel cell connectioncomponents comprises an electrically non-conductive interface regionhaving a first surface and a second surface, the first and secondsurface of the interface region being parallel to the x-z plane, thefirst surface in contact with one of the ion conducting components; andat least one electron conducting component having two surfaces parallelto the x-z plane and a length parallel to the x-z plane, one of thesurfaces of the at least one electron conducting component disposedadjacent to the second surface of the interface region, wherein the atleast one electron conducting component comprises conductive fibersoriented parallel to the x-z plane and oriented at an angle of greaterthan 0″ and less than 90° to the first or second surface of at least oneof the first or second plurality of electrode coatings; wherein the atleast one of the fuel cell connection components provides anelectrically conductive pathway between the at least one of the first orsecond plurality of electrode coatings and an external circuit orbetween the at least one of the first or second plurality of electrodecoatings and a different one of the first or second plurality ofelectrode coatings, said pathway extending along the length of the atleast one electron conducting component.